Actual Landing Research Articles

Exploration of Legal Issues in the Judicial Practice of Smart Contracts

The process of smart contracts, from conceptualization to actual landing applications, is accompanied by the continuous development of blockchain technology. China attaches great importance to the application of blockchain technology represented by smart contracts in judicial practice, with the background of the construction of smart courts, relying on the construction of judicial blockchain, according to the unique automated execution characteristics of smart contracts, the mediation and execution of civil disputes filed as an entry point, to explore the high-quality development of the judicial trial and execution business. In the current judicial practice, smart contracts face a lack of legal norms, technical construction loopholes, and information security risks. To guarantee the reasonable and compliant stable operation of smart contracts within the legal framework, it is necessary to clarify the legal positioning of smart contracts, strengthen the construction of the rule system for the judicial application of smart contracts, introduce the ODR to broaden the rights' relief channels, and at the same time, encourage the participation of diversified subjects in the construction of the judicial blockchain, and establish the legalized review mechanism of smart contracts.

Aircraft turnaround time dynamic prediction based on Time Transition Petri Net.

Accurate aircraft turnaround time prediction is an important way to coordinate the operation time of airport ground service and improve the efficiency of airport operation. In this paper, by analyzing the aircraft turnaround operation process, a description model based on Time Transition Petri Net is proposed. The model describes the flight turnaround operation process and the logical relationship of the operation. According to the model, a dynamic prediction method of turnaround time based on Bayesian theorem is designed. According to the actual landing time of the flight, the aircraft turnaround time is predicted. The specific method is to obtain the prior probability distribution and joint distribution law of each operation link according to the flight history data, and use Shapiro-Wilke to test the prior probability distribution of each link. Based on the analysis and comparison between the actual turnaround data of a large airport in China and the forecast data proposed in this paper, the root-mean-square error 3.75 minutes and the mean absolute error 3.40 minutes can be calculated. This paper contributes to the improvement of flight punctuality rate and airport clearance level.

Research on Intelligent Control Method of Launch Vehicle Landing Based on Deep Reinforcement Learning

A launch vehicle needs to adapt to a complex flight environment during flight, and traditional guidance and control algorithms can hardly deal with multi-factor uncertainties due to the high dependency on control models. To solve this problem, this paper designs a new intelligent flight control method for a rocket based on the deep reinforcement learning algorithm driven by knowledge and data. In this process, the Markov decision process of the rocket landing section is established by designing a reinforcement function with consideration of the combination effect on the return of the terminal constraint of the launch vehicle and the cumulative return of the flight process of the rocket. Meanwhile, to improve the training speed of the landing process of the launch vehicle and to enhance the generalization ability of the model, the strategic neural network model is obtained and trained via the form of a long short-term memory (LSTM) network combined with a full connection layer as a landing guidance strategy network. The proximal policy optimization (PPO) is the training algorithm of reinforcement learning network parameters combined with behavioral cloning (BC) as the reinforcement learning pre-training imitation learning algorithm. Notably, the rocket-borne environment is transplanted to the Nvidia Jetson TX2 embedded platform for the comparative testing and verification of this intelligent model, which is then used to generate real-time control commands for guiding the actual flying and landing process of the rocket. Further, comparisons of the results obtained from convex landing optimization and the proposed method in this work are performed to prove the effectiveness of this proposed method. The simulation results show that the intelligent control method in this work can meet the landing accuracy requirements of the launch vehicle with a fast convergence speed of 84 steps, and the decision time is only 2.5 ms. Additionally, it has the ability of online autonomous decision making as deployed on the embedded platform.

Analysis of the salmon fishing season of 2022

Pacific salmon fishery in the Far East of Russia in 2022 is analyzed. The reasons for discrepancy between forecasted and actual landing of pacific salmon are discussed. Measures to improve the management and scientific support of the pacific salmon fishery are proposed.

Normal force on the asteroid regolith generated by the impact of lander footpad

The landing of a probe on the surface of an asteroid can produce a stable operating platform and obtain vital data describing the mechanical response of the asteroid material. The fine-grained regolith area on the asteroid surface is essential in cushioning the probe from impact energy and in avoiding the risk raised by the large protruding rocks during the landing of the probe. Models incorporating macro forces explaining the interaction between the landing terminal of the probe and the regolith on the asteroid surface conclusively reflect the mechanical process and characteristics of the interaction, making them particularly suitable to analyze and control the landing process of the probe. In this paper, we study the macro normal force of the interaction between the footpad of a legged probe and the regolith on the asteroid surface with particular attention paid to the mathematical expression of the force model and the contribution of the most essential soil parameters. The ultimate bearing theory of soil mechanics is extended to discuss the mathematical model of the macro normal force on the asteroid regolith in a micro-gravity environment undergoing different damage modes. Subsequently, a series of discrete element method simulations are implemented to verify the normal force model and to analyze its characteristics under the influence of landing impact. On the basis, the effect modes of several most essential soil parameters of soil porosity, particle size and cohesive strength are revealed through a robust regression analysis of the simulation data. Next, the correlation coefficients of the effects of soil parameters on the macro normal force are researched. The model of macro normal force established in this paper can be used to facilitate an effective performance analysis in the development of the landing-cushioning mechanism of the probe, as well as to conclude a reference for the most essential soil properties parameters of the asteroid regolith via the inverse solution of the interaction data recorded in actual landing missions.

Rapid Generation of the Fuel-Optimal Trajectory for Landing on Irregularly Shaped Asteroids

In an asteroid soft landing mission, the irregularly distributed gravitational field and unexpected external disturbances may lead to a significant deviation of the actual landing trajectory to the predesigned trajectory. Therefore, the capability of trajectory onboard generation is essential to meet the requirements of landing accuracy and safety. To this end, this article proposes a rapid trajectory generation algorithm for the fuel-optimal asteroid landing. First, two important properties of the fuel-optimal landing trajectory are revealed in detail with the presented theorems. Then, based on these properties, the problem of landing trajectory generation is transformed into an onboard parameter searching problem, which is of significant benefit for the real-time performance and convergence. The effectiveness of the proposed algorithm is verified through the 433 Eros soft landing mission based numerical simulations. It is shown that the proposed fuel optimal asteroid landing trajectory generation algorithm is valid with deviated initial conditions and irregularly distributed gravitational field.

Application of Random Region Augmentation Algorithm in Deep Learning

In the field of computer vision, the collection and sorting of image data is the core driving force. However, the current data collection work cannot perfectly collect the image data of each actual landing scene. The purpose of the data augmentation algorithm is to increase the diversity of the data set and improve the robustness of the model. Traditional data augmentation methods include geometric augmentation and color augmentation, mainly including flipping, rotating, cropping, translation, stretching, zooming, adding noise, blurring, Dropout, Cutout, color jittering. Traditional data augmentation methods have certain limitations, and the effect is not obvious. Based on the idea of Cutout algorithm, this paper proposes the RRA augmentation algorithm, which divides four quadrant regions in the image, and randomly selects the ROI region in each region, and is different from the Cutout algorithm directly discarding the region, but randomizing the region Enhance the color, and finally do geometric augmentation processing on the overall image. Compared with the original single data augmentation operation, the algorithm improves precision by 7%, and recall improves by 7%.

Estimation of aircraft turbofan engine exhaust emissions with environmental and economic aspects at a small-scale airport

PurposeThe purpose of this study is to estimate the nitrogen oxide (NOx), carbon monoxide (CO) and hydrocarbon (HC) emissions and their environmental and economic aspects during the actual landing and take-off operations (LTO) of domestic and international flights at a small-scale airport. In this regard, the aircraft-induced NOx, CO and HC emissions analyses, the global warming potential (GWP) estimations of exhaust emissions and the life cycle assessment (LCA)-based environmental impact (EI) estimations of exhaust emissions, and the eco-cost estimation of exhaust emissions are measured.Design/methodology/approachEstimations and calculations are performed in parallel with the International Civil Aviation Organisation’s Engine Emission Databank and Intergovernmental Panel on Climate Change approaches. Also, to assess the environmental effect of the pollutants, the GWP and the EI analyses which is based on the LCA approaches are used. Finally, the eco-cost approach has been used to discuss the economic aspects of these emissions.FindingsThe total emissions of air pollutants from aircraft are estimated as 601.067 kg/y for HC, 6,074.905 kg/y for CO and 4,156.391 kg/y for NOx at the airport. Also, emissions from international flights account for 79% of emissions from all flights. The Airbus A321 type of aircraft has accounted for more than half of the total HC, CO and NOx emissions. The total amount of emissions from the B738 type of aircraft is estimated as 24%. It is noticed that the taxi phase constitutes 52% of the total HC, CO and NOx emissions. Because of this, it is selected the five different alternative taxi times to observe the effects of pollution role of taxiing time in detail and re-estimated accordingly. According to the re-estimated results with variations in taxiing time, when the taxiing time at the airport is 24 min instead of the original value, this case contributes to a decrease in total LTO emissions of approximately 4%. Also, when the taxiing time is decreased by 2 min, HC, CO and NOx emission amounts decrease by approximately 3.9%, 5.9% and 1.2%, respectively. At this point, the polluting role of taxiing time will be helpful to reduce the aircraft-induced HC, CO and NOx emissions for other larger-scale airports. On the other hand, it is estimated that the GWP of the A321 is 1,066.29 t CO2e whilst the GWP of B738 is 719.50 t CO2e. The eco-cost values of the A321, B738, A320 and CL60-type of aircraft are estimated as almost 61,049.42, 41,086.02, 18,417.43 and 6,163.59 Euros, respectively.Practical implicationsWith the detailed results of this study, the polluting role of taxiing time on total HC, CO and NOx emissions in a small-scale airport will be helpful to reduce aircraft-induced emissions for other larger-scale airports. Also, in the future, this study and its results will be helpful to create an emission inventory at the airport examined.Originality/valueIn this study, different from some previous studies, air pollutants from aircrafts are evaluated with different aspects such as the EI and eco-cost and GWP. Also, this study will be making a helpful contribution to the literature as it covers the more diversity of the different types of aircrafts in the analyses.

드론의 로봇팔(RAD)을 이용한 청소 로봇의 기울어진 태양광 패널위의 랜딩 실험연구

In this paper, the landing experiment of the Solar Panel Cleaning Robot(Dr.SPC) by a drone is presented. The robot arm for a drone (RAD) is designed to have two degrees-of-freedom to carry the cleaning mobile robot. The end-effector of the arm is equipped with an electromagnet to hold and release the robot electrically. The end-effector of the robot arm also has two ultrasonic sensors to measure the slanted angle of the panel and a camera to see the panel closely. Measuring the slanted angle of a solar panel is used for the arm to tilt the cleaning robot in parallel with the panel to minimize the contact force measured by a force sensor mounted on the first link. A drone is replaced with an x-y table for the planar motion of the arm. Actual landing experiments of Dr. SPC on the panel are conducted to test the feasibility.

Numerical modeling of lander interaction with a low-gravity asteroid regolith surface

Context.The JAXA asteroid sample return mission Hayabusa2 reached its target (162173) Ryugu in June 2018 and released the European (CNES-DLR) lander MASCOT in October 2018. MASCOT successfully landed on the surface, and the Hayabusa2 Optical Navigation Camera system has been able to image parts of the MASCOT trajectory.Aims.This work builds on our previous study of interactions between a landing package and a granular material in the context of MASCOT on Ryugu. The purpose is to expand our knowledge on this topic and to help constrain physical properties of surfaces by considering the actual trajectory of MASCOT and observations of Ryugu from Hayabusa2.Methods.We ran a new campaign of numerical simulations using theN-body codepkdgravwith the soft-sphere discrete element method by expanding the parameter space to characterize the actual landing scenario of MASCOT on Ryugu. The surface was modeled as a granular medium, but we also considered a large boulder in the bed at various depths and a rigid wall representing a cliff. MASCOT was faithfully modeled as the actual lander, and we considered different impact angles, speeds, and surface slopes. We were particularly interested in the outgoing-to-incoming speed ratio of MASCOT during the landing process.Results.We found that a boulder in the bed generally increases both the stochasticity of the outcomes and the speed ratio, with larger increases when the boulder sits closer to the surface. We also found that the surface slope does not affect our previous results and that the impact speed does not affect the speed ratio for moderate-friction granular material. Finally, we found that a speed ratio as low as 0.3, as estimated in the actual scenario, can occur with a solid-rock surface, not only with a soft surface, because the geometry of the lander is nonspherical. This means that we must infer the physical properties of the surface from outcomes such as the speed ratio with caution: it depends on the lander geometry.

Fatigue Life Prognosis of a Light Aircraft Landing Gear Leg

Aircraft components are subject to fatigue damage. The prediction of fatigue life has significant influence on maintenance and flight operations. Light aircraft, designed for recreational purposes, have vital components that are subject to a hard time maintenance approach. The focus of this article is on a simple method for predicting fatigue life. The method is applied to a light aircraft’s fixed landing gear leg. The landing gear leg is modelled in a computer aided design environment. The load spectrum is determined, based on a characteristic flight profile. Principal strains are determined with finite element analysis. Fatigue life is calculated with the Coffin-Manson low cycle fatigue relation. The Palmgren-Miner rule is applied, and cumulative damage is determined. The results are compared to actual landing gear leg fatigue damage and the hard time replacement interval which is given in the corresponding maintenance manual.

Diffusion phenomenon of lunar soil particles under a plume in a vacuum environment by numerical simulation

During the landing of lunar probes on the surface of the Moon, lunar soil particles are lifted and diffused under the action of a plume. This study used three methods to numerically investigate the diffusion of lunar soil particles under a plume in a vacuum environment. First, an analytical solution of Fick's second law is used to obtain the motion results of lunar soil particles under the influence of diffusion in a steady state. Then, Fick's second law of finite-difference solution is used to obtain the motion results under the influence of diffusion. Finally, the discrete solution method of the mass- and energy-conservation equations is used to determine how the particles are affected by the plume in a transient state, including effects such as drag and lift, gravity, and temperature. The results show that lunar soil particles with small diameters diffuse more easily. After considering diffusion, the diffusion speeds of the 10- and 40-μm lunar soil particles are 3.6–4.5 times the speeds of those without diffusion; the spatial distribution range is increased by 1.4–4.5 times. The maximum lifting angle is increased by 1.0°–1.6°. However, lunar soil particles with diameters of 70 and 100 μm are not considerably affected by diffusion. At the same time, the introduction of the energy-loss coefficient showed that the impact of energy loss on the diffusion effect is substantial and that greater energy losses result in more diffusion-weakening trends. Compared with energy loss without considering the energy loss, diffusion speed is reduced by 10.2%–50.6%, occupied space is decreased by 18.3%–48.5%, and lifting angle is decreased by 18.8%–21.8%.Among the three methods, the mass- and energy-conservation method can fully consider the effects of particles and other factors. After considering the diffusion effect, the spatial distribution of lunar soil particles coheres better with the actual landing pictures, confirming that the impact of lunar soil particle diffusion on spatial distribution cannot be ignored.

Contact Force/Torque Control Based on Viscoelastic Model for Stable Bipedal Walking on Indefinite Uneven Terrain

Humanoid robots are being designed to perform tasks currently carried out by human workers in industry, manufacturing, service, and disaster assistance. To this end, the humanoid robot should be able to walk stably across many types of terrain. However, when traversing a complex unknown environment, it is difficult to realize accurate terrain perception immediately through large data collected by the sensor system, leading to a difference between planned foot landing positions and actual foot landing positions. As a result, an unexpected contact force/torque may affect the stability of the robot. This paper adopts active contact perception instead of terrain perception and proposes a contact force/torque control method based on the viscoelastic model to address this problem. In addition, we design a body stability controller based on tracking the trajectories of the virtual repellent point (VRP) and the divergent component of motion (DCM) to restrain the disturbance caused by the unexpected contact force/torque. Simulations and experiments on the BHR-6P humanoid robot platform demonstrate the proposed contact force/torque control method for walking on indefinite uneven terrain. Note to Practitioners —This paper presents a contact force/torque controller based on a viscoelastic model, which unifies contact perception and adaptive reaction. Using the viscoelastic model, we get the relationship between the end position/posture and the first-order differential of the contact force/torque, from which a state equation can be established and used to design a state feedback controller. Combining with body stabilization, we adopt this controller to modify the trajectory of both landing and support feet simultaneously for humanoid robots to realize stable bipedal walking on indefinite uneven terrain, which is validated in both simulations and experiments on the BHR-6P humanoid robot. In addition, this method can be employed for other robots or equipment when the contact force/torque control is needed; e.g., industry manipulators and quadruped robots.

The Beagle has landed: Past Forward_By Allison Marsh

In 1968, the popular comic strip character Snoopy became a safety mascot for NASA. The next year, the indefatigable beagle headed to the moon. The crew of Apollo 10, tasked with performing a dress rehearsal for Apollo 11, named their lunar module "Snoopy." Their command module was, naturally, "Charlie Brown." On 22 May, astronauts Eugene Cernan and Tom Stafford descended in Snoopy but stopped, as instructed, some 14,000 meters above the lunar surface. The actual landing would wait for Neil Armstrong and company. Meanwhile, in the Peanuts universe, Snoopy and his flying doghouse touched down on the moon four months before Apollo 11. "I beat the Russians…I beat! everybody," the astrobeagle marveled as he took his first steps. "I even beat that stupid cat who lives next door!"

GNSS-based navigation systems of autonomous drone for delivering items

This paper presents our research on the development of navigation systems of autonomous drone for delivering items that uses a GNSS (Global Navigation Satellite System) and a compass as the main tools in drone. The grand purpose of our research is to deliver important medical aids for patients in emergency situations and implementation in agriculture in Indonesia, as part of the big mission of Society 5.0 and related with big data. In sending process, drone must be able to detect object and reach goal position and go back safely using GPS. We proposed a navigation algorithm for drone including the usage of course-over-ground information to help drone in doing autonomous navigation. In the experiment that we did, the average of positional deviation of landing position between the actual landing position and the desired landing position in the flight tests of flying from start to goal is 1.1125 m and for the tests that use the algorithm which uses course-over-ground, the positional deviation has average of 2.39 m. Navigation using course-over-Ground algorithm is not more reliable than the navigation algorithm with GNSS and Compass at a navigation distance of less than 1 m.

GORE TAG Thoracic Endograft with Active Control System: Landing Accuracy and Wall Apposition in an Initial Clinical Experience

The aim was to describe a single-center experience with the Conformable GORE TAG Thoracic Endoprosthesis (C-TAG) with active control system, specifically designed to evaluate the accuracy of proximal and distal deployment and its capability to adapt to the aortic wall. This is a single-center prospective study including all patients treated with the C-TAG with active control system for thoracic aorta pathologies from September 2017 to May 2018. Proximal and distal accuracy of deployment was measured as the distance between "intended" and "actual landing" zone measured on the digital subtraction angiography images. Mean lack of wall apposition was measured at postoperative computed tomography (CT) angiogram images as the distance between the proximal or distal graft radiopaque ring marker and the point of graft aortic complete apposition, using parasagittal multiplanar reconstructions. Eleven cases were treated: 6 atherosclerotic aneurysms (5 descending and 1 arch), 1 dissecting aneurysm, 2 type B acute dissections, 1 thoracic pseudoaneurysm, and 1 Kommerell diverticulum. The proximal deployment was in landing zone 3 in 6 cases (54%), 2 in 2 cases (18%), 1 in 1 case (9%), and 0 in 2 (18%). The distal landing was in zone 4 in 1 case (9%), zone 5 in 9 cases (81%), and in 1 case (9%), it was in zone 6 with intentional coverage of the celiac trunk. Rapid pacing was used only in 2 cases. Mean accuracy of deployment was 1.8±1.3mm for the proximal and 0.7±1mm for the distal landing zones. Mean lack of wall apposition was 1.1±1.9mm at the proximal landing zone and 0.6±1.8mm at the distal landing zone. The C-TAG with active control system offers accurate deployment both at the proximal and at the distal levels. The conformability, staged deployment, and angulation control allow good adaptation to aortic arch and precise deployment.

What goes up must come down: biomechanical impact analysis of falling locusts.

Many insects are able to precisely control their jumping movements. Once in the air, the properties of the actual landing site, however, are almost impossible to predict. Falling insects thus have to cope with the situation at impact. In particular, for insects jumping to escape predators, a controlled landing movement appears to be a major evolutionary advantage. A quick recovery into an upright and stable body posture minimizes the time to prepare for the next escape jump. In this study, we used high-speed recordings to investigate the falling and in particular the impact behavior of Schistocerca gregaria locusts, a common model organism for studies on the biomechanics of jumping. Detailed impact analyses of free-falling locusts show that most insects typically crashed onto the substrate. Although free-falling locusts tended to spread their legs, they mostly fell onto the head and thorax first. The presence of wings did not significantly reduce impact speed; however, it did affect the orientation of the body at impact and significantly reduced the time to recover. Our results also show that alive warm locusts fell significantly faster than inactive or dead locusts. This indicates a possible tradeoff between active control versus reduced speed. Interestingly, alive insects also tended to perform a characteristic bending movement of the body at impact. This biomechanical adaptation might reduce the rebound and shorten the time to recover. The adhesive pads also play an important role in reducing the time to recover by allowing the insect to anchor itself to the substrate.

Flower pollination algorithm with runway balance strategy for the aircraft landing scheduling problem

Aircraft landing scheduling is a challenging problem in the field of air traffic, whose objective is to determine the best combination of assigning the sequence and corresponding landing time for a given set of aircraft to a runway, and then minimize the sum of the deviations of the actual and target landing times under the condition of safe landing. In this paper, a flower pollination algorithm embedded with runway balance is proposed to solve it. Context cognitive learning and runway balance strategy are devised here to enhance its searching ability. 36 scheduling instances are selected from OR-Library to validate its performance. The experimental results show that the proposed algorithm can get the optimal solutions for instances up to 100 aircrafts, and is also capable of obtaining better solutions compared with SS, BA and FCFS for instances up to 500 aircrafts in a shorter time.

Investigating actual landing and takeoff operations for time-in-mode, fuel and emissions parameters on domestic routes in Turkey

Operational landing and takeoff standards developed by the International Civil Aviation Organization (ICAO) in the 1970s, have been widely-used in fuel consumption and emissions models or inventory studies. However, these generic standards may cause significant uncertainties due to changes in the air transport system over time and appear to remain highly conservative. To quantify the uncertainty caused by using generic operational standards, in this study, the effects of actual fuel flow and time-in-mode of more than 9000 different domestic flights, performed by five different narrow-bodied aircraft models with seven different engine, on the averages of landing and takeoff fuel burn and emissions are investigated. Compared to the simple approach, suggested by the ICAO, results indicate considerably lower time in mode averages, particularly during taxi-out (42%) and climb (45%) phases, even for high traffic volume airports. The greatest differences in fuel flow are observed during takeoff and approach phases. As a result of using actual time-in-mode and fuel flow data, the actual landing and takeoff fuel burn averages are found to be 35% lower than ICAO values. In addition, the effects of low altitude level flight on approach phase fuel flow, thrust reverser mode on taxi-in phase fuel flow, and stop and acceleration of aircraft on taxi ways on fuel flow are discussed. With regard to emissions, using actual time-in-mode and fuel flow data, landing and takeoff cycle hydrocarbon and carbon monoxide emissions are found to be 34% lower, while nitrogen oxide emissions are found to be 38% lower than those given by the ICAO database. Analyses related to the effects of aircraft mass on emissions indicate that the differences for carbon monoxide and nitrogen oxides between the lightest and heaviest aircraft are 3% and −26%, respectively. The analyses results reveal that uncertainties in landing and takeoff fuel burn and emissions caused by considering ICAO time-in-modes can be significantly higher compared to those caused by considering ICAO fuel flow standards.

A Novel Landing System to Increase Payload Capacity and Operational Availability of High Altitude Long Endurance UAVs

Unmanned stratospheric aircraft capable of staying aloft for long periods of time have become a topic of interest in the past years. Several problems are still to be solved to allow for a profitable commercial use of such aircraft. The inherent lightweight design leads to fragile structures with low payload capacities and a high wind sensitivity. The weather dependence significantly reduces the system’s operational availability. To address these drawbacks a novel landing system is proposed in this paper. The landing gear can be removed from the aircraft and a ground-based mobile landing platform is introduced. The main technical challenges consist in the precise relative state estimation and cooperative control of the involved vehicles. A reliable simulation model of the overall system was developed and a number of simulation experiments performed before the actual landing was attempted with an experimental system setup. Multiple successful landing experiments demonstrate the validity of the proposed system.